# Define and invoke function.
def sum(a,b):
    return a+b
func = sum
r = func(5,6) #function name alias
print(r)
r = sum(5,7)
print(r)
# Defines function with default argument
def add(a,b=2):
    return a+b
r=add(1)
print(r)
r=add(1,5)
print(r)
